/*
 * utilities
 *
 *
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */


#ifndef _TM_UT_H
#define _TM_UT_H


#include "../../core/proxy.h"
#include "../../core/str.h"
#include "../../core/parser/parse_uri.h"
#include "../../core/dprint.h"
#include "../../core/ut.h"
#include "../../core/ip_addr.h"
#include "../../core/error.h"
#include "../../core/forward.h"
#include "../../core/mem/mem.h"
#include "../../core/parser/msg_parser.h"
#include "../../core/resolve.h"
#ifdef USE_DNS_FAILOVER
#include "../../core/dns_cache.h"
#include "../../core/cfg_core.h" /* cfg_get(core, core_cfg, use_dns_failover) */
#endif


/*! Which header fields should be skipped */
#define tm_skip_hf(_hf)                                       \
	(((_hf)->type == HDR_FROM_T) || ((_hf)->type == HDR_TO_T) \
			|| ((_hf)->type == HDR_CALLID_T) || ((_hf)->type == HDR_CSEQ_T))


/* a forced_proto takes precedence if != PROTO_NONE */
inline static enum sip_protos get_proto(
		enum sip_protos force_proto, enum sip_protos proto)
{
	/* calculate transport protocol */
	switch(force_proto) {
		case PROTO_NONE: /* no protocol has been forced -- look at proto */
			switch(proto) {
				case PROTO_NONE: /* leave it to dns */
					return PROTO_NONE;
				case PROTO_UDP: /* transport specified explicitly */
#ifdef USE_TCP
				case PROTO_TCP:
				case PROTO_WS:
#endif
#ifdef USE_TLS
				case PROTO_TLS:
#endif
#ifdef USE_SCTP
				case PROTO_SCTP:
#endif
					return proto;
				case PROTO_WSS: /* should never see ;transport=wss */
				default:
					LM_ERR("unsupported transport: %d\n", proto);
					return PROTO_NONE;
			}
		case PROTO_UDP: /* some protocol has been forced -- take it */
#ifdef USE_TCP
		case PROTO_TCP:
		case PROTO_WS:
#endif
#ifdef USE_TLS
		case PROTO_TLS:
		case PROTO_WSS:
#endif
#ifdef USE_SCTP
		case PROTO_SCTP:
#endif
			return force_proto;
		default:
			LM_ERR("unsupported forced protocol: %d\n", force_proto);
			return PROTO_NONE;
	}
}


/*
 * Convert a URI into a proxy structure
 */
inline static struct proxy_l *uri2proxy(str *uri, int proto)
{
	struct sip_uri parsed_uri;
	struct proxy_l *p;
	enum sip_protos uri_proto;

	if(parse_uri(uri->s, uri->len, &parsed_uri) < 0) {
		LM_ERR("bad_uri: [%.*s]\n", uri->len, uri->s);
		return 0;
	}

	if(parsed_uri.type == SIPS_URI_T) {
		if(parsed_uri.proto == PROTO_UDP) {
			LM_ERR("bad transport for sips uri: %d\n", parsed_uri.proto);
			return 0;
		} else if(parsed_uri.proto != PROTO_WS)
			uri_proto = PROTO_TLS;
		else
			uri_proto = PROTO_WS;
	} else
		uri_proto = parsed_uri.proto;
#ifdef HONOR_MADDR
	if(parsed_uri.maddr_val.s && parsed_uri.maddr_val.len) {
		p = mk_proxy(&parsed_uri.maddr_val, parsed_uri.port_no,
				get_proto(proto, uri_proto));
		if(p == 0) {
			LM_ERR("bad maddr param in URI <%.*s>\n", uri->len, ZSW(uri->s));
			return 0;
		}
	} else
#endif
		p = mk_proxy(&parsed_uri.host, parsed_uri.port_no,
				get_proto(proto, uri_proto));
	if(p == 0) {
		LM_ERR("bad host name in URI <%.*s>\n", uri->len, ZSW(uri->s));
		return 0;
	}

	return p;
}


/*
 * parse uri and return send related information
 * params: uri - uri in string form
 *         host - filled with the uri host part
 *         port - filled with the uri port
 *         proto - if != PROTO_NONE, this protocol will be forced over the
 *                 uri_proto, otherwise the uri proto will be used
 *                 (value/return)
 *         comp - compression (if used)
 * returns 0 on success, < 0 on error
 */
inline static int get_uri_send_info(
		str *uri, str *host, unsigned short *port, char *proto, short *comp)
{
	struct sip_uri parsed_uri;
	enum sip_protos uri_proto;

	if(parse_uri(uri->s, uri->len, &parsed_uri) < 0) {
		LM_ERR("bad_uri: %.*s\n", uri->len, uri->s);
		return -1;
	}

	if(parsed_uri.type == SIPS_URI_T) {
		if(parsed_uri.proto == PROTO_UDP) {
			LM_ERR("bad transport for sips uri: %d\n", parsed_uri.proto);
			return -1;
		} else if(parsed_uri.proto != PROTO_WS)
			uri_proto = PROTO_TLS;
		else
			uri_proto = PROTO_WS;
	} else
		uri_proto = parsed_uri.proto;

	*proto = get_proto(*proto, uri_proto);
#ifdef USE_COMP
	*comp = parsed_uri.comp;
#endif
#ifdef HONOR_MADDR
	if(parsed_uri.maddr_val.s && parsed_uri.maddr_val.len) {
		*host = parsed_uri.maddr_val;
		LM_DBG("maddr dst: %.*s:%d\n", parsed_uri.maddr_val.len,
				parsed_uri.maddr_val.s, parsed_uri.port_no);
	} else
#endif
		*host = parsed_uri.host;
	*port = parsed_uri.port_no;
	return 0;
}


/*
 * Convert a URI into a dest_info structure.
 * Same as uri2dst, but uses directly force_send_socket instead of msg.
 * If the uri host resolves to multiple ips and dns_h!=0 the first ip for
 *  which a send socket is found will be used. If no send_socket are found,
 *  the first ip is selected.
 *
 * params: dns_h - pointer to a valid dns_srv_handle structure (initialized!) or
 *                 null. If null or use_dns_failover==0 normal dns lookup will
 *                 be performed (no failover).
 *         dst   - will be filled
 *         force_send_sock - if 0 dst->send_sock will be set to the default
 *                 (see get_send_socket2())
 *         sflags - send flags
 *         uri   - uri in str form
 *         proto - if != PROTO_NONE, this protocol will be forced over the
 *                 uri_proto, otherwise the uri proto will be used if set or
 *                 the proto obtained from the dns lookup
 * returns 0 on error, dst on success
 */
#ifdef USE_DNS_FAILOVER
inline static struct dest_info *uri2dst2(struct dns_srv_handle *dns_h,
		struct dest_info *dst, struct socket_info *force_send_socket,
		snd_flags_t sflags, str *uri, int proto)
#else
inline static struct dest_info *uri2dst2(struct dest_info *dst,
		struct socket_info *force_send_socket, snd_flags_t sflags, str *uri,
		int proto)
#endif
{
	struct sip_uri parsed_uri;
	enum sip_protos uri_proto;
	str *host;
#ifdef USE_DNS_FAILOVER
	int ip_found;
	union sockaddr_union to;
	int err;
#endif

	if(parse_uri(uri->s, uri->len, &parsed_uri) < 0) {
		LM_ERR("bad_uri: [%.*s]\n", uri->len, uri->s);
		return 0;
	}

	if(parsed_uri.type == SIPS_URI_T) {
		if(parsed_uri.proto == PROTO_UDP) {
			LM_ERR("bad transport for sips uri: %d\n", parsed_uri.proto);
			return 0;
		} else if(parsed_uri.proto != PROTO_WS)
			uri_proto = PROTO_TLS;
		else
			uri_proto = PROTO_WS;
	} else
		uri_proto = parsed_uri.proto;

	init_dest_info(dst);
	dst->proto = get_proto(proto, uri_proto);
#ifdef USE_COMP
	dst->comp = parsed_uri.comp;
#endif
	dst->send_flags = sflags;
#ifdef HONOR_MADDR
	if(parsed_uri.maddr_val.s && parsed_uri.maddr_val.len) {
		host = &parsed_uri.maddr_val;
		LM_DBG("maddr dst: [%.*s:%d]\n", parsed_uri.maddr_val.len,
				parsed_uri.maddr_val.s, parsed_uri.port_no);
	} else
#endif
		host = &parsed_uri.host;
#ifdef USE_DNS_FAILOVER
	if(cfg_get(core, core_cfg, use_dns_failover) && dns_h) {
		ip_found = 0;
		do {
			/* try all the ips until we find a good send socket */
			err = dns_sip_resolve2su(dns_h, &to, host, parsed_uri.port_no,
					&dst->proto, dns_flags);
			if(err != 0) {
				if(ip_found == 0) {
					if(err != -E_DNS_EOR)
						LM_ERR("failed to resolve \"%.*s\" :"
							   "%s (%d)\n",
								host->len, ZSW(host->s), dns_strerror(err),
								err);
					return 0; /* error, no ip found */
				}
				break;
			}
			if(ip_found == 0) {
				dst->to = to;
				ip_found = 1;
			}
			dst->send_sock =
					get_send_socket2(force_send_socket, &to, dst->proto, 0);
			if(dst->send_sock) {
				dst->to = to;
				return dst; /* found a good one */
			}
		} while(dns_srv_handle_next(dns_h, err));
		LM_ERR("no corresponding socket for \"%.*s\" af %d\n", host->len,
				ZSW(host->s), dst->to.s.sa_family);
		/* try to continue */
		return dst;
	}
#endif
	if(sip_hostport2su(&dst->to, host, parsed_uri.port_no, &dst->proto) != 0) {
		LM_ERR("failed to resolve \"%.*s\"\n", host->len, ZSW(host->s));
		return 0;
	}
	dst->send_sock =
			get_send_socket2(force_send_socket, &dst->to, dst->proto, 0);
	if(dst->send_sock == 0) {
		LM_ERR("no corresponding socket found for \"%.*s\" af %d (%s:%s)\n",
				host->len, ZSW(host->s), dst->to.s.sa_family,
				proto2a(dst->proto), su2a(&dst->to, sizeof(dst->to)));
		/* ser_error = E_NO_SOCKET;*/
		/* try to continue */
	}
	return dst;
}


/*
 * Convert a URI into a dest_info structure
 * If the uri host resolves to multiple ips and dns_h!=0 the first ip for
 *  which a send socket is found will be used. If no send_socket are found,
 *  the first ip is selected.
 *
 * params: dns_h - pointer to a valid dns_srv_handle structure (initialized!) or
 *                 null. If null or use_dns_failover==0 normal dns lookup will
 *                 be performed (no failover).
 *         dst   - will be filled
 *         msg   -  sip message used to set dst->send_sock and dst->send_flags,
 *                 if 0 dst->send_sock will be set to the default w/o using
 *                  msg->force_send_socket (see get_send_socket()) and the
 *                  send_flags will be set to 0.
 *         uri   - uri in str form
 *         proto - if != PROTO_NONE, this protocol will be forced over the
 *                 uri_proto, otherwise the uri proto will be used if set or
 *                 the proto obtained from the dns lookup
 * returns 0 on error, dst on success
 */
#ifdef USE_DNS_FAILOVER
inline static struct dest_info *uri2dst(struct dns_srv_handle *dns_h,
		struct dest_info *dst, struct sip_msg *msg, str *uri, int proto)
{
	snd_flags_t sflags;
	if(msg)
		return uri2dst2(dns_h, dst, msg->force_send_socket, msg->fwd_send_flags,
				uri, proto);
	SND_FLAGS_INIT(&sflags);
	return uri2dst2(dns_h, dst, 0, sflags, uri, proto);
}
#else
inline static struct dest_info *uri2dst(
		struct dest_info *dst, struct sip_msg *msg, str *uri, int proto)
{
	snd_flags_t sflags;
	if(msg)
		return uri2dst2(
				dst, msg->force_send_socket, msg->fwd_send_flags, uri, proto);
	SND_FLAGS_INIT(&sflags);
	return uri2dst2(dst, 0, sflags, uri, proto);
}
#endif /* USE_DNS_FAILOVER */

#endif /* _TM_UT_H */
